Multiplex telegraph system.



BATNTEDl AUG'. 4, 1908.

. AA. W'. DOUGLAS.

.MULHPLEX TELEGRAPH SYSTEM.A

l`^AI'ILIGATIN FILED APB. 13,1907.

Q gusanito: Amar Vil/Joa( AMOR w. Donor-as.;QR'ALRUQURRQUE, freRRiroRiv or New MEXICO.

MULTIPLX TELEGRAPH SYSTEM.

No. 895,350.V p

Specification of Letters Patent, i

Application-filed April 13, 1907. Serial No. 368,003.

To all whom it may concern:

Be it known that I, AMOR W. DOUGLAS, a citizen of the United States, residing at Albuquerque., in the county of Bernalillo and '.l`erritory of New Mexico, have. invented new and useful Improvements mMultiplex Tele- -graph Systems, of which the following is a specification.

This invention relates to multi lex telegraph systems of that type in whic i sending and receiving signaling apparatus responsive to alternating current are employed in connection with a simple Morse system.

The invention has for one of its objects to improve and simplify the construction and operation of telegraph systems of this character so as to be comparatively easy and inexpensive to manufacture and keep in repair, thoroughly reliable arid efficient in use, and readily manipulated.

A further object of the invention is the provision of a multiplex telegraph system in which the source of alternating current is located only at the main or central oflice, thus obviating the necessity of skilled attendants, not only atthe main station, but at the distant or secondary stations of the system according to other multi lex systems employing alternating currents or transmitting messages.

A still further object of the invention is the provision of secondary or sub-station sending and receiving sets which are extremely simple in organization so that they can be manipulated by operators of average intelligence, it being necessary merely to cut the sets into the line wires when it is desired to transmit a larger number of messages than is possible by tIrc Morse sets as at busy times and to cut the alternating currentsets out of service during less busy times.

Another object is to employ a single source of alternating current for supplying a plurality of line wires in which are included the continuous and alternating current sets, the organization of the system being such that. the inductive effect of current in one line is minimized as regards the other or others and the alternating current source or generator is connected in multiple relation with the several line wires through independent transformers.

Il'ith these obiects in view and others, as will appear as the description proceeds, the invention comprises the various novel. fea- Pacentea Aug. 4, loos. A

tures of construction and arrangement of i parts which will be more fully described hereinafter and set forth with partioularity in the 'i claims appended hereto.

In the accompanying drawing, which illustrates one of the embodiment-s of the mventlon, the figure 1s a diagram of the c1rcu1ts of the system.

Referring to the drawing, m and m designate respectively the two line wires extending from the main office ofthe system designated generally by M to distant way oflices O and O and secondary stations A and B. At the main station M are Morse sets N and N connected respectively with the line wires 'm and m and continuous or uni-directional current is supplied for signaling lby the Morse sets N and N', and O and O from a battery or generator by the conductors l and 2. The Morse sets at the. main and way stations are of the usual character, 'as will be readily understood, and the ends of the linev wires opposite from the source of continuous current will be connected to a battery or generator and to ground for the return currents to pass back to the battery b through the earth. Bridging each set at the way stations O and O is a condenser c forming a shunt around the said sets for the alterhating currents passing through the line wires.

In the line wires are choke coils I and I at the main station or office and I" and I3 at the secondary oilices A and B, rcs ectively, and for short cirouiting these co` s, switches S are employed.

At the main stat-ion or oflice M is an alternating current gen erator AC that has oneof its' brushes connected'by the branch conductor 3 with the primary coils p of transformers T and T and the opposite sides of the primary coils are connected with the other brush of the generator by conductors 4 and 5 res ectively, that include the armatures a' am a of Sounders s and s controlled by the keys K and K which are normally closed. The secondary coils s A'of the main transformers are connected in series with the line wires, so

that when the rimary circuits are closed by the keys K an( K', each line wire will have impressed thereon an alternating electrometor force which is used for transmitting messages between the alternating current sets of the main stati-cn or office' M and the second- I ary ofcesAandB. -V I.

i l l. l

vmay be c.osed.

Although the secondary stations or offices are not shown equipped with ordinary Morse sets, it' is to be understood that they are'employed in actual practice in conjunction with the alternating signaling sets. At the main office are arranged a lurality of .sending and receiving sets C antFD which, in organization, are like the sets at the offices A. and B and the circuits of the sets-A and C are inductively related to the line Wire m by transformers t and t' respectively, While the sets B and D are inductively related to the line wire mby transformers t2 and t3 respectively.

Each circuit of the sets AyB etc., mcludes a relay r bridged by a condenser c and whose armature a controls the local circuit of a reeatmg sounder b winch in turn controls the oca] cncuit of a reading sounder d. Asso-,

ciated with each alternating current signal- Y ing set, both at the main and secondarylofces, is a conductor 8 including a variable re-' slstance R and a condenser` c2 Whlch may be adjustable, each conductor S at the mam station being connected to ground at 6 through- The the armature of sounders o and o. Sounders s and o, and s and o', are each in a local circuit including a battery e, the key K controlling one circuit and the key K', the other. The primary coil of each alternating current signaling set and the circuitthereof including the relay and adjustable condenser forms a sta-tie circuit and normally the armature of the relay is held by its spring in a position to maintain the local circuit of the repeating sounder or relay b closed. In the present diagram, the key K is shown closed and the key K open, While the keys k and c are in closed position.

When thebusiness on the system is such that it can be conveniently handled by the Morse sets, the alternating current signaling sets are cut out 0f service and the switches S In sending messages, the current asses from the battery b to either or both Fines through the switches S, sounding relays and keys of the Morse setsineluded in the lines. Willen, however, the al ternating current signaling sets are connected in circuit, the switches S are opened and the continuous current passes through the induction coils in the lines 1u and m during the signaling by the Morse sets. Any number of way oHices may be provided and the continuous current, after passing through the sets at these stations, returns by way of the earth to the battery in the usual manner.

A Then it is desired to bring the alternating current signaling set at the sta-tion A or B into service for handling an accumulation of business, the operator communicates the fact from such station to 'the operator at the main station by meansof the Morse instruments and the main operator instructs the seconda-ry station operator to cut his signaling set into service, it being understood that A.c2 l 'A 895,350`

thefsecondary coils of the transformers t and t vare provided with double plugs at the ends nearest to the main office that are adapted to be plugged intojacks suitably arranged, while' the conductors S are provided with double plugs 4adapted to be plugged into' jacks at the ends of thlsecondary coils farthest from the main 'slation, as will be readily understood. V Then by operating the kev.-

lc or c, a message can be transmitted to th'el 'C set C or D at the main office.

Assuming that a message is to be sent from the set C to the substation set A, the key K' is opened so as to open the circuit in which the primary of the transformer T is included and also the circuit including the conductor S, vresistance R and condenser c2 associated with the set C. No alternating current, therefore, is generated in the line Wires m and consequently the rcla'ys 1- of the sets C and A lose their magnetism and the armatures a are pulled by the retractile springs against the contacts of the relay or repeating sounder circuits, which Sounders :in-turn open the local circuits of the reading Sounders d.

ground 9, conductor 8, the key thereof, concenser c2, line yvire and secondaries of the transformers therein, conductor S of the set at the main station connected with said line wire, non inductive 'resistance and condenser included in` the wire, the controlling armatures of Sounders o or o', and by way of ground to the ground 9. The resistance included in the circuit reduces thecalternating current being set up in the main line wire by the generator AC to such an extent that the force of the retractile spring of the relays overcomes the weakened attractive force so that the local circuits of the repeating sou'nders open. Thus, by operating the key k or k', the operator at either of the sub-stations can signal to the operator at the main set connected with the sub-sta.tion. When any one of the line Wiresis operating with alternating current, the inductive effectthereof is diminished to a minimum as re-4 gards the other idle line Wire or wires through the medium of the induction coils included in the line Wires, as will be readily understood.

From the foregoing description, taken in Thus, by manipulating the key connection with the accompanying drawing,

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the invention appertains, and while I have described the principle of operation of the invention, together with the apparatus which I now consider to be the best embodi nient thereof, I desire to have it understood that the apparatus shown isvnierely illustrative and that such changes may be made when desired as are within the s cope of the claims. Y

1o Having thus described the invention, what- I claim is 1. In a telegraph system, the combination of a line wire, a circuit including a source of -alternating current, a transformer connecting 1.5 the circuit with the liuc wire, a grounded wire-including resistance and capacity, a local circuit includingr a battei'y, means for opening and closing the local circuit, and devices conti'olled by the said means for opening and 2; closing the source-including circuit and also the grounded conductor. Y

2. In a telegraph system, the combination of a line wire, a circuit including a source of alternating current, a transformer connecting 5 the circuit with the line wire, a grounded i, wire including resistance and capacity, a V@local circuit including a battery, means -for `opening and closing the local circuit, devices cont-rolled by the said means foi' opening and 3a 'closing the source-including circuit and also the grounded conductor, a main station signaling set at the said source and iiiductively connected with the line wire, a secondary station signaling set inductively connected with the wire, a grounded conductor at the secondary station set, and means for varying thel conductivity through the last-iiientioned conductor without opening the pat-h of current through the same for signaling from the 49 secondary to the main station.

3. In a telegraph system, the combination of a line wire, a circuit including a source of alternating current, a main station signaling set inductively connected with the line wire,

.i5 a grounded conductor, a secondary signaling set, means for opening the grounded conductor .vhen signaling from the main to the secondary station, a grounded conductor at the secondaiy station, and means for vary- .ia ing the conductivity ci' the secon l conductor without interrupting the saine i'or signaling fronithe secondar to the main station.

4. In` a multiplex telegraph system, the combination of a line wire, contiuiious current signaling devices connected therewith, a source of continuous current, means for connecting thel said source with the line wire, transformeis in the line wire, a circuit conknected with one of the transformers and i11- \53 cluding a source of alternating current, main `\and secondary signaling sets connected with the line wire, a conductor connected with the line wire to form a path. for current when signaling from the secondary to the main c5 stat-ion, means' for interrupting the conductor and firopening the source-including circuit, .and a key-including conductor connected with the line Wire at the secondary set.

The combination of a pluralityof line wires, continuous current signaling devices connected therewith, a common :source of continuous current adapted to be thrown into or out'ofmcircuit with the line wires', a main station signaling set connected witheach line wire, a secondary station signaling sei; connected with each line wire, a single alternating current generator, multiple circuits line wires including continuous current signaling sets, alternating current signaling sets' operatively related tothe line wires, a common source of current for all of the alternating current sets, choke coils included in the line wires, shortcircuiting means for the coils, and a sourceof continuous current connected with the line wires and supplying the latter through the said means.

7i In a telegraph system, the combination A of a line wire, a grounded conductor connected therewith and including resistance and capacity, a signaling set inductively related to the line wire, a source of alternating current, a circuit inductivel relating the source to the line Wire, a loca circuit including a source of current, a key for opening and clos`- ing the circuit, an electro-magnet in the local circuit having its armature contained in the alternating current circuit for o ening and closing the saine, and a second e cetro-mag` net in the local circuit and arranged with its armature to interrupt the path of current through the conductor.

8. In telegraph system, a line Wire, continuous current signaling apparatus connected therewith, signaling sets responsive to intermittent current impulses, means for inductively relating the sets to the line wire, a source of intermittent current impulses, a path including resistance and capacity leading from the line wire to ground at each set, and a means for making and breaking the circuit of the said source and siniultaneously opening and closing the said path of one of the set-s.

9. In a telegraph system, a line Wire, a plurality of signaling sets responsive to alteriiat ing current, transformers inductively relating the sets to the line wires, a plurality of continuous current signaling apparatus, a source of alternating current, a transformer inductively relating the source to the line 20 cuits and including ca s f 'i V895,350

wire, means for opening and closing the circuitof the source, a conductor at each set connected with the line, an adjustable resistance in each conductor, a Condenser as- 'making and breaking the circuit through each conductor at the same time the current of the said source is interrupted.

10. In a telegraph system, aline Wire, continuous current signaling apparatus connected therewith, a source of continuous current, induction coils connected in the line, short circuiting switches for the coils, an alternating current circuit, a transformer induct'ively relating the circuit .to the line, 4a' plurality ofsignaling apparat-us containing circuits, transformers rnductively relating the said line to the last-mentioned circuits, a conductor associated with the signaling ciracity and resistance, and a key controlling t e alternating current circuit and the said conductors. 11. In a telegraph system, a line wire, con- `\trnuous current signaling apparatus con# nected therewith, an alternating current circuit, a transformer inductively relating the circuit to the Wire, a plurality of circuits containing signaliug devices, transformers inductively relating the line with the 1ast-1nentioned circuits, a conductor in each of the lastmentioned circuits connected with the line socia-ted With said resistance, :and means for f capacity and resistance devices included in l each conductor, and a key for ma v and breaking the alternating current circuit and or grounding or ungrounding one of the said contluctors.

12. In a multiplex telegraph system, a plurality of .line Wires, a centralstation, Way and secondary stations, grounded conductors connected with the line Wires at the stations,-

continuous current signaling apparatus connected With the line Wires at the central and other stations, a plurality of circuits at the main and secondarjv stations each including signalino devices, a source of alternating current at the main station, transformers` inductively relating the circuits of the source with the line Wires, means for breaking the continuity of the alternating current and for openin one of the grounded conductors to signal rom the main to a. seco'rrdary station, and means for varying the current intensity for signaling from a secondary to the main station.

In testimony whereof, I affix my signature in presence of two Witnesses.

zmon W. DOUGLAS. l 

